The Crank to Wheel HP calculator is a simple yet practical tool that estimates the horsepower at the wheels from the crankshaft horsepower. It is an essential tool for automotive enthusiasts, mechanics, and engineers who need to understand the performance output of a vehicle’s engine and its transmission to the wheels.

**The Concept Behind the Calculator**

Horsepower (HP) is a unit of power that signifies the rate at which work is being done. In an automobile, there are typically two places where horsepower is measured: at the crankshaft (crank HP) and at the wheels (wheel HP).

Crank HP is the horsepower produced by the engine and measured at the engine’s crankshaft. This is the number that automakers usually advertise. However, the power that actually reaches the wheels (wheel HP) is less than the crank HP due to drivetrain loss.

Drivetrain loss is the decrease in power caused by the resistance within the drivetrain components, such as the gearbox, differential, and axles. A commonly used rule of thumb is that drivetrain loss accounts for about 15% of the crank HP, although this can vary depending on the specific vehicle and conditions.

**How the Crank to Wheel HP Calculator Works**

The calculator uses the following formula to estimate the wheel HP:

```
Wheel HP = Crank HP * (1 - Drivetrain Loss Percentage)
```

By assuming a drivetrain loss of 15%, the formula becomes:

```
Wheel HP = Crank HP * 0.85
```

This calculator is designed to be user-friendly and interactive. The user inputs the crank HP, and the calculator applies the formula to estimate the wheel HP. The result is displayed in a read-only field.

**Example**

Let’s say an automobile’s engine is rated at 300 crank HP. Using the calculator, we input 300 as the Crank HP. Upon clicking the ‘Calculate’ button, the calculator determines the wheel HP as follows:

```
Wheel HP = 300 HP * 0.85 = 255 HP
```

So, if the vehicle’s engine produces 300 HP at the crankshaft, approximately 255 HP will reach the wheels, accounting for a 15% drivetrain loss.

## Conclusion

The Crank to Wheel HP calculator is a valuable tool for estimating the actual power output at the wheels. It’s important to note, though, that this tool provides an estimate based on a generalized assumption of drivetrain loss. For a more accurate measurement of wheel horsepower, a dynamometer test would be necessary.